I managed to scuff my silver Pentax MX a little bit, right over the Asahi logo - nothing too bad, though I am pretty sensitive with this stuff, especially since the camera looked almost brand new prior to this.
I use the camera a lot, almost daily including winter time, so I guess it was bound to start showing some marks sooner or later.
Out of curiosity, what material is the MX - it seems to scuff/scratch more easily than most metal bodies. The bottom plate basically reveals every time it was moved around on the table. Brass with some sort of metallic coating on top?
The area under the scuff reveals a very shiny silver surface, which makes the scuff unnoticeable at some angles and -very- noticeable at other angles. I suppose trying to retouch it with anything would make matters worse...